A method and apparatus for casing recovery in which a clean-up of the inside of the outer casing above the inner casing is performed on the same trip in the wellbore as cutting and pulling a section of the inner casing. A bottom hole assembly including a spear, a casing cutter and at least one clean-up tool is described. An embodiment of a clean-up tool being a jetting sub which can jet fluid radially to wash the outer casing and selectively allow fluid to pass through the sub at different pressures is described. The jetting sub can be used to control operation of other tools in the bottom hole assembly such as the casing cutter and a hydraulic jack.

A drilling assembly (1) for making a passage in an object (2) within a petroleum well (8). The drilling assembly (1) comprises a drill bit assembly (3), a cutting assembly (4), and both assemblies (3, 4) are fastened to a rotatable drive assembly (5), the drill bit assembly (3) comprises a drill bit (31); the cutting assembly (4) comprises a hole saw assembly (42); the cutting assembly (4) is resiliently displaceable to the drill bit assembly (3). The drilling assembly (1) comprises a displaceable membrane (6) within the tubular body (41). The membrane (6) divides an interior (43) of the tubular body (41) in a receiving compartment (69) and an inner compartment (60).

A well tool for milling a tubular includes a well tubing disposed in a wellbore and including a circulation fluid pathway through an interior of the well tubing, a first milling tool coupled to the well tubing at a first longitudinal end of the well tubing, a second milling tool coupled to the well tubing at a location longitudinally uphole from the first milling tool, and a third milling tool coupled to the well tubing at a location longitudinally uphole from the second milling tool. Each of the milling tools include a mill bit and a circulation sub fluidly connected to the circulation fluid pathway. The first milling tool mills a first portion of the tubular, the second milling tool mills a second portion of the tubular, and the third milling tool mills a third portion of the tubular.

A system for retrieving a source element from a well may include a logging tool made of a first material, a milling tool, and a control device. The logging tool may include a cylindrical housing having a central chamber housing the source element and extending through a portion of the cylindrical housing along a central axis thereof. The logging tool may include a first communication device mounted on the cylindrical housing. The milling tool may include a tubing mounting structure that secures the milling tool to a tubing of the well. The milling tool may include a drill bit head made of a second material, the drill bit head may be configured for milling through the first material. The control device may include a second communication device configured to communicate with the first communication device.

An apparatus includes a gauge cutter, a lead impression block (LIB), a locking pin, and a locking device. The gauge cutter has a gauge cutter tubular body, a gauge cutter head, and an orifice. The LIB has an LIB body and an LIB head. The LIB is fixed in a first position within the orifice of the gauge cutter by being connected to an inner circumferential surface of the gauge cutter tubular body using a shear pin. The locking pin is disposed around the LIB body. The locking device is disposed around the inner circumferential surface of the gauge cutter tubular body and is configured to mate with the locking pin to hold the LIB in a second position within the gauge cutter. The second position includes a portion of the LIB body located within the orifice and the LIB head located outside of the orifice.

A method and apparatus to move an object in an open hole section of a wellbore. A bottom hole assembly including a downhole pulling tool and fishing device is described. The downhole pulling tool includes an open hole anchor to allow location of the downhole pulling tool in the open hole section of the wellbore so as to reduce the operating distance between the downhole pulling tool and the fishing device. An embodiment in which a cut section of tubular is removed from the open hole section is described. A casing cutter may also be located in the bottom hole assembly to cut the tubular on the same trip in the well as removing the cut section of tubular.

A drilling assembly comprises a drill bit and a cutting assembly. The drilling assembly forms a longitudinal center axis. The drill bit and cutting assembly fastened to a rotatable spline drive assembly. The cutting assembly resiliently displaceable to the drill bit along the center axis such that in a first position the drill bit is surrounded by the cutting assembly, and in a second position a free end portion of the drill bit is projecting beyond the cutting assembly along the center axis. The cutting assembly comprises an endmill. The endmill comprises a central through hole complementary to the outer diameter of the drill bit. A method for cutting swarfs created by drilling, with an endmill, is described.

A location of a cut and an amount of force to be used in a pull operation for a plug & abandonment (P&A) operation can be determined. Measurements of at least one characteristic of fluids and solids disposed in an annulus defined between a casing and a wall of a wellbore can be received. A total fluid and solid friction force drag can be determined using hydrostatic force that is determined from the measurements. A mechanical friction force drag can be determined based on a weight of the casing. The mechanical friction force drag and the total fluid and solid friction force drag can be used to determine a friction factor. The friction factor can be used to determine a depth location at which to cut the casing and a pull force for pulling the casing from the wellbore in the P&A operation.

Systems and methods for drilling a geothermal well can include drilling a vertical borehole to a target location, drilling a plurality of lateral boreholes, each of which is connected to the vertical borehole, and can include generating a plurality of chambers in at least one of the plurality of lateral boreholes. The techniques can include drilling a plurality of passageways that each provide fluid communication between one of the plurality of chambers in a first lateral borehole and a second lateral borehole of the plurality of lateral boreholes. The techniques can form a fluid circuit for injecting a heating fluid such as water or brine and recovering hot water and steam using a single vertical borehole. The hot water and/or steam can be used to generate electrical power with a geothermal power facility.

A method of recovering casing from a wellbore in which: a logging tool is run to an estimated stuck point of the casing through the central bore of the casing spear and casing cutter; the casing spear is attached to the casing and tension applied so that logging can be performed over a length at an estimated stuck point both with and without tension to provide the verified stuck point; and the casing cutter is positioned relative to this to cut the free casing; and the spear used to remove it. The method can be performed on a single trip. Embodiments include incorporating a packer to circulate fluid during casing cutting; a disconnect, anchor mechanism and motor to allow use of a motor to operate the cutter; and a Down Hole Power Tool with a method of establishing the required force to recover a length of stuck casing.